ISSN:0044-5983    

DOI:10.1111/j.1438-8677.1994.tb00729.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

SUMMARYBalanites aegyptiaca(L) Del. has a trizonate ovule primordium and an elongated bitegmic, crassinucellate and anatropous ovule. The dermal inner and outer integument are about 4–5‐layered and the inner layer of the inner integument becomes slightly endothelial. After fertilization the nucellus and subsequently the inner integument are resorbed. The outer integument ultimately becomes about 30‐layered. The cells of the inner layer of the outer integument divide once periclinally. The vascularized seed‐coat consists of parenchyma cells with scattered, lignified sclerenchyma elements. Ovule and seed characters support the recognition of a separate family Balanitaceae and a relationship with an enlarged order

ISSN:0044-5983    

DOI:10.1111/j.1438-8677.1994.tb00730.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

SUMMARYSeed‐coat development inRanunculus sceleratusL. has been studied by electron microscopy. Three layers developed from the single integument. The outer epidermis consisted of elongated and flattened cells that were always well attached to each other. The cells were characterized by thin walls, the presence of chloroplasts and small vacuoles. The cells of the middle layer were originally closely packed. Gradually, extensive intercellular spaces were formed. The cells of the inner epidermis elongated initially, until they became cubic and developed a thick wall with numerous wall ingrowths at the side bordering the nucellus. Thus, they give rise to a mechanical layer protecting the inner part of the seed.The elongation of cells, the thickening of cell walls, the formation of wall ridges, and the formation of intercellular spaces each coincided with characteristic configurations of microtubules. Plasmodesmata were originally found between all cells of the integument but their number decreased drastically during development, especially between the three developing seed‐coat layers. Well‐differentiated chloroamyloplasts, present in all cells of the developing seed‐coat, pointed to autotrophy during development.Maturation eventually led to the disappearance of cytoplasm in all cells, the compression of the cells of the outer epidermis and middle layers, and the formation of a mechanical layer from the inner ep

ISSN:0044-5983    

DOI:10.1111/j.1438-8677.1994.tb00731.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

SUMMARYThe nitrate content of seeds of the annualSisymbrium officinalewas raised by weekly nitrate fertilizations of the seeding mother plants. Nitrate content and germination of the seeds produced were positively correlated. Seed lots with different endogenous nitrate contents were buried at 10 cm in sandy loam. At regular intervals seeds were exhumed and germination was tested. Both the initial differences in endogenous nitrate content and the differences of germination rapidly diminished during burial because nitrate rapidly leached from the seeds. The sensitivity of exhumed seeds to applied nitrate strongly varied during this 1‐year study. Sensitivity to nitrate was low in December and had increased in January‐February probably because of low winter temperatures. A cold pretreatment in Petri dishes also strongly increased sensitivity to nitrate. Endogenous nitrate content of seeds collected in the field was much lower than reported in this study and therefore the differences in seed‐nitrate content in the field probably are of limited ecological significance. A high endogenous nitrate content will stimulate germination only temporarily. In contrast, the changes in sensitivity in nitrate seem ecologically important because they will restrict germination ofS. officinaleto seasons suitable for survival of the seed

ISSN:0044-5983    

DOI:10.1111/j.1438-8677.1994.tb00732.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

SUMMARYGeneral organization and ultrastructure of pistil transmitting tract (PTT) for pollen tube pathway in wheat(Triticum aestivumL.) and pollen tube growth were studied. The peculiar features of cell ultrastructure in different parts of the PTT were shown and point to heterogeneous pollen tube pathway. Stylodia TT cells show protein and carbohydrate secretion. In stylar TT cells dark globules are secreted. In the ovarian cavity fibrillar material is present.The organization of pollen tube cytoplasm also changes during its growth towards the ovule. The thickness of the callose layer of the pollen tube wall decreases in the direction of the ovule. In the stylar TT the pollen tube plasma membrane forms finger‐like protrusions, or plasmotubules, which can connect the neighbouring pollen tubes. The role of these plasmodesmata‐like formations in the pollen tube and their role in the interaction of pollen tubes with PTT in different parts of pollen tube pathway in wheat are discus

ISSN:0044-5983    

DOI:10.1111/j.1438-8677.1994.tb00733.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

SUMMARYThe reversion of the highly sphericalras1−phenotype of the sterile mutant ofSchizosaccharomyces pombewas examined by fluorescence microscopy of Calcofluor‐ and rhodamine phalloidin‐labelled cells and by freeze‐fracturing. Rapid and dramatic changes occurred in cell shape after a nutritional stimulus, with cells regaining their rod‐like cell shape during successive cell divisions. This was achieved by restoration of the cell wall architecture and of the invaginated state of the plasma membrane. This is the first demonstration of a nutrient‐induced reversion ofras1−S. pombecells from rounded to rod‐

ISSN:0044-5983    

DOI:10.1111/j.1438-8677.1994.tb00734.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

ISSN:0044-5983    

DOI:10.1111/j.1438-8677.1994.tb00735.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Book reviewed in this article:Quantitative Approaches to PhytogeographyP.L. Nimis and T.J. CrovelloTransplant Production Systems. Proceedings of the International Symposium on Transplant Production Systems, Yokohama, Japan, 21–26 July 1992K. Kurata and T. Kozai (eds)Towards Rational Use of High Salinity Tolerant Plants. Vol. 1H. Lieth and A.A. Al Masoom (eds)Hybrid Wheat: Results and Problems. Advances in Plant Breeding: Fortschritte der Pflanzenzüchtung, Band 15. Adrian A. Pickett.Pigment‐Protein Complexes in Plastids: Synthesis and AssemblyChrister Sundqvist&Margareta Ryberg (eds).Plant Biochemistry and Molecular BiologyPeter J. Lea and Richard C. Leegood (eds).Cellular and Molecular Aspects of the Plant Hormone EthyleneJ.C. Pech, A. Latché and C. Balagué (eds).Molecular and Cell Biology of the Plant Cell CycleJ.C. Ormrod and D. Francis (eds).Sexual Plant ReproductionM. Cresti and A. Tiezzi (eds).Biotechnology in AgricultureC. You, Z. Chen and Y. Ding (eds).Exkursionsflora für die Kanarischen InselnA. Hohenester and W. Weiss.Progress in Botany, Vol. 54H.‐D. Behnke, U. Lüttge, K. Esser, J.W. Kadereit and M. R

ISSN:0044-5983    

DOI:10.1111/j.1438-8677.1994.tb00736.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

ISSN:0044-5983    

DOI:10.1111/j.1438-8677.1994.tb00737.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

ISSN:0044-5983    

DOI:10.1111/j.1438-8677.1994.tb00738.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY